| From f89fcf9e5afcda7c263be488d359cdf0008b8e3e Mon Sep 17 00:00:00 2001 |
| From: Sven Van Asbroeck <thesven73@gmail.com> |
| Date: Fri, 26 Apr 2019 14:36:35 -0400 |
| Subject: rtc: 88pm860x: prevent use-after-free on device remove |
| |
| [ Upstream commit f22b1ba15ee5785aa028384ebf77dd39e8e47b70 ] |
| |
| The device's remove() attempts to shut down the delayed_work scheduled |
| on the kernel-global workqueue by calling flush_scheduled_work(). |
| |
| Unfortunately, flush_scheduled_work() does not prevent the delayed_work |
| from re-scheduling itself. The delayed_work might run after the device |
| has been removed, and touch the already de-allocated info structure. |
| This is a potential use-after-free. |
| |
| Fix by calling cancel_delayed_work_sync() during remove(): this ensures |
| that the delayed work is properly cancelled, is no longer running, and |
| is not able to re-schedule itself. |
| |
| This issue was detected with the help of Coccinelle. |
| |
| Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com> |
| Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/rtc/rtc-88pm860x.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/drivers/rtc/rtc-88pm860x.c b/drivers/rtc/rtc-88pm860x.c |
| index d25282b4a7dd1..73697e4b18a9d 100644 |
| --- a/drivers/rtc/rtc-88pm860x.c |
| +++ b/drivers/rtc/rtc-88pm860x.c |
| @@ -421,7 +421,7 @@ static int pm860x_rtc_remove(struct platform_device *pdev) |
| struct pm860x_rtc_info *info = platform_get_drvdata(pdev); |
| |
| #ifdef VRTC_CALIBRATION |
| - flush_scheduled_work(); |
| + cancel_delayed_work_sync(&info->calib_work); |
| /* disable measurement */ |
| pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0); |
| #endif /* VRTC_CALIBRATION */ |
| -- |
| 2.20.1 |
| |
